[PATCH v4 4/7] Bluetooth: hci_sync: hold conn in hci_connect_pa_sync() callback

[Pauli Virtanen]

There is theoretical UAF if the conn is freed while the hci_sync task is
running.

Hold refcount to avoid that.

Fixes: 6d0417e4e1cf ("Bluetooth: hci_conn: Fix not setting conn_timeout for Broadcast Receiver")
Signed-off-by: Pauli Virtanen <pav@xxxxxx>
---

Notes:
    v4:
    - no change
    v3:
    - split to multiple patches per different Fixes:

 net/bluetooth/hci_sync.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index d8efd143135a..56018214120b 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -7198,7 +7198,7 @@ static void create_pa_complete(struct hci_dev *hdev, void *data, int err)
 	bt_dev_dbg(hdev, "err %d", err);
 
 	if (err == -ECANCELED)
-		return;
+		goto done;
 
 	hci_dev_lock(hdev);
 
@@ -7222,6 +7222,8 @@ static void create_pa_complete(struct hci_dev *hdev, void *data, int err)
 
 unlock:
 	hci_dev_unlock(hdev);
+done:
+	hci_conn_put(conn);
 }
 
 static int hci_le_past_params_sync(struct hci_dev *hdev, struct hci_conn *conn,
@@ -7360,8 +7362,11 @@ int hci_connect_pa_sync(struct hci_dev *hdev, struct hci_conn *conn)
 {
 	int err;
 
-	err = hci_cmd_sync_queue_once(hdev, hci_le_pa_create_sync, conn,
+	err = hci_cmd_sync_queue_once(hdev, hci_le_pa_create_sync,
+				      hci_conn_get(conn),
 				      create_pa_complete);
+	if (err)
+		hci_conn_put(conn);
 	return (err == -EEXIST) ? 0 : err;
 }
 
-- 
2.54.0